U.S. Pat. No. 2,463,860 to Foster shows a handle-clamp device that is used with a portable chainsaw.
U.S. Pat. No. 2,973,673 to Grau discloses a portable drill attachment used in converting a portable hand drill to a drill press. A handle-clamp assembly is provided to adjust the height of a drill above the work piece.
U.S. Pat. No. 2,664,768 to Clyne describes a motion limiting device that is used to quickly and easily adjust the depth on a drill press. The device includes a knurled knob on a threaded rod. Adjustment is accomplished by depressing a spring and moving the knob manually to the desired position.